THE AGE OF MAMMALS 



side of its nose. As large as the rhinoceros but having 

 a very different arrangement of the bones of its ankles 

 and wrists and very different teeth and horns are the 

 extraordinary creatures known as Dmocerafs, whole skele- 

 tons of which have been disinterred from the Eocene 

 strata of Wyoming in the United States by Professor 

 Marsh. These creatures had three pairs of horns on the 

 top of the head and a pair of great tusks as well. Nearly 

 all these animals, though they were more brainy than the 

 reptiles, had much smaller brains in proportion to their 

 size than the bulk of the animals which now roam the 

 earth, from which we may surmise that though a small 

 brain suffices to guide a great animal machine in estab- 

 lished ways, yet in order to learn new things in its life- 

 time an animal must have a big brain. 



The last great mammal we must mention in this series is 

 the Arsinoitherium, which was found only a few years ago 

 by Dr. Andrews in Egypt, in the same strata whence he 

 obtained the fossil ancestors of the elephant. It was so 

 called because it was found near the palace of Arsinoe, 

 the name of the Egyptian queen of Greek race. But 

 ArsmoitTierium was far from being a graceful ladylike 

 creature, and, resembling in general appearance a rhino- 

 ceros, had two enormous bones, which grew out of its 

 nose on either side of it. The bones were hollow and 

 were probably covered with skin in life ; and Arsinoitherium 

 had a wonderful and wonderfully even set of teeth. To 

 conclude, we must add a representative mammal of this 

 period, the Sivatherium, found in India, and the Samo- 

 therium, found in the Isle of Samos, which were like 



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